Emerging investigator series: synthesis of magnesium oxide nanoparticles fabricated on a graphene oxide nanocomposite for CO2 sequestration at elevated temperatures

Abstract

Alkaline metal oxides incorporated into porous templates are considered novel chemisorbents for capturing greenhouse gases including CO₂ at elevated temperatures. Thus, magnesium oxide nanoparticles (MONPs) and MONP incorporated graphene oxide (MONP–GO) were synthesized using a sol–gel method. Preparation of these materials was carried out by a three-step facile synthesis route involving: (1) synthesis of magnesium oxide (MO) nanoparticles (MONPs), (2) synthesis of graphene oxide (GO) from commercially available graphene, and (3) incorporation of MONPs on graphene oxide. Both MONP and MONP–GO samples exhibited a significantly high CO₂ uptake of 2.79–3.34 mmol g⁻¹ at two different elevated temperatures (60 and 120 °C). The increased CO₂ adsorption is due to the presence of terminal OH groups and acid–base pair sites at the magnesium (Mg²⁺–O²⁻) surface in the MONP and MONP–GO materials, respectively, resulting in the formation of hydrogen carbonate species and bidentate carbonate complexes with CO₂ gas. Our composite material also possesses intriguing properties including high thermal and chemical stabilities, low-cost, and environmental benignity along with its enhanced CO₂ sorption making it an excellent candidate for CO₂ capture in fossil fuel-based power plants at elevated temperatures.